This 2000 photo shows the Mid-Hudson Bridge (US 44 and NY 55) from the Highland anchorage. (Photo by Steve Anderson.)

PLANNING, DESIGN AND CONSTRUCTION: One of three bridges built across the Hudson River in the space of a decade, the Mid-Hudson Bridge represented state-of-the-art thinking in long-span suspension bridge design. When plans were announced for the Mid-Hudson Bridge by state legislators J. Griswold Webb and John M. Hackett in 1923, there was no fixed Hudson River crossing south of Albany that was open to automobile traffic. Two other vehicular crossings, the Bear Mountain Bridge and the Holland Tunnel, were under construction at the time. In June 1923, Governor Alfred E. Smith signed the bill authorizing construction of the Mid-Hudson Bridge. Under this bill, the New York State Department of Public Works (NYSDPW) was to construct the bridge.

Rudolphe Modjeski, one of the premier bridge designers of the early twentieth century, oversaw the design and construction aspects of the Mid-Hudson Bridge. Modjeski was familiar with the area, since in 1907 he had been charged with strengthening the Poughkeepsie Railroad Bridge, a massive truss span that represented state-of-the-art design when it opened in 1888. Initial test borings were made in May 1925, and the cornerstone was laid on October 9th of that year. Additional construction contracts were awarded in June 1926.

The concrete caissons - concrete blocks that have an upside-down U shape - that support the towers were sunk 115 feet below water on the western side, and 135 feet below water on the eastern side. Each caisson, equal in bulk to a 12-story building, weighed 66,000 tons. These were set into the riverbed with the open end facing straight down, and then the dirt beneath was dug out as weight is put on top of the caisson to push it into the riverbed until it hits solid rock.

Unlike newer bridges that use clamshell buckets from above water level to dig out the flooring, the Mid-Hudson Bridge was built using manned caissons. Under this painstaking process, workmen would get into the pressurized cavity of the caisson and slowly remove the earth with pick axes and shovels. The dirt and the men would leave the caisson through an airlock that ran from the top of the caisson to the work chamber. The process was not without risk: a severe tilt developed in the east caisson, delaying construction for over a year. More than 80 feet below the Hudson River, workmen slowly shifted the east caisson, back to perpendicular with pulleys and dredging over the course of two years, at the rate of 18 inches per day.

In April 1929, under contract from the American Bridge Company, work began on the superstructure. Once the caissons were firmly established, the 315-foot-tall steel towers, spaced 1,500 feet apart (the distance of the main suspension span), were erected. The exposed surfaces of the two Gothic-design towers were encased in granite. After the towers were completed, work began on spinning the two 16¾-inch-diameter main cables (each composed of 6,080 wires) and suspending cables, followed by the truss-stiffened bridge deck. Construction proceeded smoothly until the superstructure was completed 16 months later.

LEFT: Preliminary work on the bridge deck before the roadway is placed. RIGHT: Eleanor Roosevelt, at that time the First Lady of New York, cuts the ribbon opening the Mid-Hudson Bridge in 1930. (Photos by New York State Bridge Authority.)

THE BRIDGE OPENS: On August 25, 1930, Governor Franklin D. Roosevelt opened the span between Highland, Ulster County to the west, and Poughkeepsie, Dutchess County to the east. When it opened, the bridge provided two lanes of traffic across the Hudson, one lane in each direction. It also provided a walkway for pedestrian and bicycle traffic. Upon opening, the bridge toll was 80 cents for automobiles, and 10 cents for pedestrians and cyclists. In 1933, the Mid-Hudson Bridge was taken over by the New York State Bridge Authority.

MEETING POSTWAR TRAFFIC NEEDS: As more motorists took to the road in the postwar era, the Mid-Hudson Bridge and its approaches have made modified several times to handle ever-increasing traffic loads. The first such project came in 1949, when the eastern approach in Poughkeepsie was widened from two to three lanes. The project also added a third tollbooth to expedite motorists through the toll plaza.

During the 1960's, new arterial highways were constructed from both approaches of the Mid-Hudson Bridge. Designed to help traffic between the bridge and surrounding communities flow smoothly, the approaches aroused serious controversy. In one instance, an elderly woman in the path of the proposed highway tenaciously held onto her home until road crews arrived at her front door.

The new approaches are described as follows:

The eastern approach in Poughkeepsie opened in September 1966. It includes an interchange with a short controlled-access section of north-south US 9. Like many interchanges from the 1950's and 1960's, the ramps to US 44-NY 55 are situated within the median of the US 9 Expressway. Furthermore, all entrances and exits from the US 9 Expressway are on the left, and all left-turn movements involve a U-turn onto the opposing roadway.

The western approach and new toll plaza in Highland opened in December 1967. It includes a trumpet interchange with north-south US 9W. The former western approach was converted into a cul-de-sac leading to Johnson-Iorio Park.

PRESERVING A MODERN LANDMARK: In 1983, the American Society of Civil Engineers designated the Mid-Hudson Bridge as a New York State Historic Civil Engineering Landmark. Since then, projects have been undertaken to ensure the integrity of the bridge for decades to come.

In the summer of 1983, the existing two-lane roadway on the bridge was widened to three lanes. Under normal conditions, one lane is open to traffic in each direction, while the center lane is kept closed. During rush hour periods, the center lane is used for the dominant flow of traffic.

Wear and tear on the 57-year-old roadway prompted officials at the New York State Bridge Authority to undertake an extensive, two-year-long deck replacement project during the late 1980's. Most work was done in the overnight hours, with one lane of traffic moving in alternating directions to keep interruption of traffic to a minimum. The authority ensured smooth rush hour traffic flow by threatening monetary penalties for failure to open the bridge in the morning.

In order to facilitate work and inspections under the bridge, four "travelers," or large mobile platforms, were installed just beneath the decking girders. The travelers, which run between the anchorages, towers and mid-span, move approximately two miles per hour to allow maintenance, repairs and inspections of the superstructure. These platforms are also being used during the current repainting project.

In 1994, the bridge was ceremonially renamed the "Franklin D. Roosevelt Mid-Hudson Bridge" in honor of the former Governor and President. However, most people still refer to the span simply as the Mid-Hudson Bridge. Part of US 44 and NY 55, the Mid-Hudson Bridge now carries approximately 35,000 vehicles per day (AADT) between Poughkeepsie and Highland. This figure represents a 75 percent increase over 1980 traffic levels.

Type of bridge:Construction started:Opened to traffic:Length of main span:Length of side spans:Length, anchorage to anchorage:Total length of bridge and approaches:Number of traffic lanes:Width of roadway:Height of towers above mean high water:Clearance at center above mean high water:Number of cables:Diameter of each of two cables:Total number of wires in each cable:Structural material: Tower material:Deck material: Cost of original structure:

SOURCES: "New Bridge Over the Hudson at Poughkeepsie," The New York Times (8/21/1930); "Governor Proposes Hudson Bridge Body," The New York Times (8/25/1930); Road to Ruin by A.Q. Mowbray, J.B. Lippincott Company (1969); Engineers of Dreams by Henry Petroski, Vintage Books-Random House (1995); "Bridges Spanning the Hudson" by Krisy Nigro, Marist College (1999); Modjeski and Masters; New York State Bridge Authority; New York State Department of Transportation; Nathan W. Perry; Christof Spieler.